Energy dissipation in hydraulic jumps on horizontal rough beds

Hydraulic jump is an important phenomenon for hydraulic engineers. It has received a significant attention since last century, as it usually occurs in correspondence with hydraulic structures. In river restoration projects, it is quite usual to protect the stilling basin bed with coarse materials. Therefore, a correct assessment of the hydraulic jump properties on rough beds assumes a fundamental importance in the perspective of a correct management of rivers rehabilitation. In particular, hydraulic jump can be used as an efficient and economic energy dissipater. Nevertheless, there is still a lack of knowledge on the energy dissipation process in the presence of rough beds in different relative roughness conditions. Therefore, the present paper aims to analyze the effects of both relative roughness and inflow Froude number on the energy dissipation in a large range of bed configurations. Four different bed materials were tested and a useful relationship was derived to predict the dissipative phenomenon.